Israeli troops launched a major ground offensive preparing for a significant expansion and ABC's Alex Marquardt is on the ground with the latest. Good morning, Alex. Reporter: Good morning, George. Thousands of Israeli troops poured into the gaza strip overnight. Backed by tanks on the ground and planes in the sky. Israel says the goal is not to occupy gaza or to destroy hamas but to significantly weaken the group and stop the rocket fire into Israel. Reporter: From land, sea and air, Israel's punishing bombardment of gaza overnight lit up the dark sky. Then the order was given to launch the ground operation. Columns of Israeli tanks and troops moving into the gaza strip on the order of the prime minister. Their primary mission, to destroy the huge network of tunnels that hamas uses to carry out attacks on Israel. Tunnels that Israel's relentless air campaign over the past ten days hasn't been able to take out. Prime minister netanyahu now says he's ready to significantly expand the ground operation to deal harsh blows to hamas and their arsenal. Today, we saw the devastating aftermath of Israel's bombing this morning. The family here tells us they came to this house evacuating from another area thinking it would be safer. They were taking refuge right here during the bombing when a tank shell burst through the wall killing three including two children. This man lost his brother and son. He told me that he wants no cease-fire. That hamas should keep firing rockets. Those killed in this house and elsewhere overnight raised the death toll to more than 260 Palestinians including almost 60 children. On the Israeli side, two have now died. One Israeli soldier killed in the overnight operation. For now there is relative quiet here in gaza. I was just out walking around. There are some people in the streets doing some shopping but they know this calm likely won't last.

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